https://interactions.guidetherapeutiquevih.com/en/interaction-details?id=13654

Darunavir / cobicistat

Rifabutin

Avoid association.

No pharmaceutical opinion available for this interaction.

Mechanism

Darunavir / cobicistat can inhibit the metabolism (CYP 3A4) and increase the plasma concentration of Rifabutin.

Rifabutin can induce the metabolism (CYP 3A4) and decrease the plasma concentration of Darunavir / cobicistat.

Darunavir / cobicistat

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Risk of a possible development of resistance to antiretroviral class.

Recommendations

Association not recommended. If used, closely monitor clinical effectiveness.

Choose an alternative.

Alternative solution(s)

Protease inhibitor boosted with ritonavir or dolutegravir 50 mg QD or raltegravir 400 mg BID or raltegravir HD 1200 mg QD : see dolutegravir + rifabutin or raltegravir + rifabutin.

Rifabutin

Pharmacodynamic effects

Possible increase of adverse effects.

Recommendations

Avoid this combination, otherwise a decrease in the dose is necessary.

Dose reduction suggested of up to 75% (e.g., 150 mg every other day).

Monitor closely clinical efficacy and appearance of adverse effects.

Alternative solution(s)

–

Monitor

Rifabutin adverse effects : rash, taste alterations, anorexia, nausea, insomnia, facial paralysis, twitching, peripheral neuritis, neutropenia, thrombocytopenia, arthralgia, uveitis, elevation of liver function tests.

Tests

Rifabutin

Blood count

Liver function

Darunavir plasma level

CD4+

Viral load HIV

Pharmacokinetic parameters

–

Comment

Several studies were initially done with healthy subjects with the combination of protease inhibitors and rifabutin. These studies demonstrated that a dose of rifabutin 150 mg 3 times/week associated with protease inhibitors was approximately equivalent to a dose of rifabutin 300 mg QD.
Subsequently, studies in subjects co-infected with HIV and tuberculosis demonstrated that the dose of 150 mg 3 times/week was insufficient for some subjects.

Ref #3117 : To optimize the monitoring for rifabutin, dosage of this agent, at equilibrium (t1/2 normal; 25hrs), may be necessary. The targeted therapeutic index of 0.3-0.9μg/ml 3-4 post dose (Cmax) and a dose reduction may be necessary from 1 μg/ml depending on the clinical context.

Reference
  • 3071
    Darunavir/cobicistat (Prezcobix), Janssen, Ontario, Canada, 7 avril 2017.
  • 1096
    Rifabutin (Mycobutin), Pfizer, Québec, Canada, 22 juin 2015.
  • 3117
    Regazzi M, Carvalho AC, Villani P, Matteelli A. Treatment Optimization in Patients Co-Infected with HIV and Mycobacterium tuberculosis Infections: Focus on Drug–Drug Interactions with Rifamycins. Clinical Pharmacokinetics, June 2014, 53 (6), 489-507.
  • 3116
    Center for Disease Control and prevention. Managing Drug Interactions in the Treatment of HIV-Related Tuberculosis. Disponible: http://www.cdc.gov/tb/publications/guidelines/tb_hiv_drugs/recommendations03.htm Publié le 22 sept 2014. Consulté le 11 janvier 2018.
  • 3151
    U.S. Department of Health and Human services (DHHS) : Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents Living with HIV. Disponible : https://clinicalinfo.hiv.gov/en/guidelines/hiv-clinical-guidelines-adult-and-adolescent-arv/whats-new. Publié le 6 décembre 2023. Consulté le 20 février 2024.
  • 3437
    Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (Symtuza), Janssen Inc, Ontario, Canada, 3 octobre 2018.